SHARPSBURG, Maryland (AP) -- Members of the Ku Klux Klan and other white supremacist groups rallied Saturday at the Antietam National Battlefield, believed to be the first time a group was given permission to demonstrate at the site of the bloodiest day of the Civil War.

About 30 people, some in white robes and others in the military-style clothing and swastika armbands of the National Socialist Movement of America, stood next to a farmhouse on the battlefield. Some delivered speeches attacking immigrants, blacks and other minority groups.

About 200 federal, state and local officers watched to ensure peace and to act as a buffer between the Klan and about 30 counter-demonstrators.

Antietam carries powerful symbolism, said Gordon Young of the Ku Klux Klan.

"As the Klan, we are the ghosts of our Confederate brothers and sisters who died here," Young said.

The protest was the third by extremist groups at national parks in the past three years.